1. Field of the Invention
The present invention relates to modular electrical connectors and, more particularly, to card edge connectors with shielded modular inserts.
2. Discussion of Earlier Developments
There is a plethora today of known constructions of multiple contact electrical connectors providing a variety of features including some form of modular construction and signal shielding. A few of the more pertinent patented constructions known to the applicants will now be briefly described.
U.S. Pat. Nos. 4,067,637 to Narozny, No. 4,324,451 to Ammon et al. and 4,530,561 to Tyree et al. are generally descriptive of currently used card edge connectors.
U.S. Pat. No. 4,550,959 to Grabbe et al. discloses an expandable, modular card edge connector in which individual elements are unified into a longitudinal whole by melting an interfacing material between adjoining sections. Withdrawal of the heat source results in a generally rigid assembly.
U.S. Pat. No. 4,586,254 to Ammon et al. discloses a modular printed circuit card edge connector in which two end bodies engage opposite ends of a single insulator body which contains the entire population of contacts. It is intended to be manufactured in a generally long bar, or by a continuous molding process, to provide for cutting to length a single, unitary housing component containing the desired number of contact arrays.
U.S. Pat. No. 5,013,263 to Gordon et al. and U.S. Pat. No. 5,584,728, both disclose an electrical connector built up of interlocking modules. Specifically, the connector structures have conversely shaped interlocking parts at their ends to interlock end-to-end with similar structures to form a substantially self-supporting structure that can have any desired number of contacts, each spaced an integral multiple of the same unit distance from all of the contacts on all of the modules.
U.S. Pat. No. 5,104,341 to Gilissen et al. discloses an electrical connector mountable to a printed circuit board which includes a plurality of insulated housings. The housings accept a plurality of terminal subassemblies into which a plurality of electrical terminals are integrally molded. Shield members are insertable into the rear of the connector housing to shield adjacent vertical rows of terminals from cross talk.
U.S. Pat. No. 5,704,793 to Stokoe et al. discloses an electrical connector which is scalable in its engagement widths, but not by means of combinations of contact modules. The scalable components of this invention are contained within a longitudinal latching and clamping mechanism. This invention uses a single and discrete membrane such as a flex circuit, which must be clamped on to the card edge pattern by the latching and clamping mechanism.
U.S. Pat. No. 5,716,237 to Conorich et al. discloses an electrical connector which compensates from near-end cross talk at its mating section with near-end cross talk of an opposite polarity and essentially equal magnitude. Conductive plates connected to the conductors of the connector provide capacitive coupling unbalance between the adjacent pairs of conductors to produce the necessary opposite polarity, equal magnitude, near-end cross talk.
The present invention relates, generally, to a card edge connector which includes an elongated longitudinally extending outer frame defining a reception region. The electrical connector is adapted to receive a plurality of chiclet modules including contact members lying in parallel laterally extending planes which, as an assembly, are positioned to connectively engage with mating contacts. Each chiclet module includes an insulative housing having first and second spaced generally parallel elongated passages therein and a card receiving recess for reception therein between the first and second passages of a planar card having opposed surfaces with conductive contact members thereon. First and second elongated contacts are firmly received, respectively, in the first and second passages. Each has a first contact surface positioned, respectively, for engagement with first and second of the mating contacts. The card receiving recesses of the chiclet modules as a group define a longitudinally extending card receiving slot. The elongated contacts each include a second contact surface projecting into the card receiving slot for engagement, respectively, with second conductive contact members on the planar card. A tubular ground shield may be slidably received on the insulative housing in proximate engagement with its outer peripheral surface. In this instance, the ground shield includes a first integral ground contact for engagement with a ground contact of an external unit associated with the mating contacts engaged by the first contact surfaces of the first and second elongated contacts and a second integral ground contact for engagement with a ground contact surface on the planar card inserted into the card receiving slot.
A chiclet module may be described as a pre-assembled module which includes one or more contacts, an insulator, and one or more shields. The pre-assembly of identical modules creates an advantageous economy of scale. Modular chiclet designs can be easily built or altered to afford interconnection of the exact number of contacts desired, relieving the user of having to select an oversized connector.
Each chiclet module can independently mate to a designated pattern of pads positioned along a substrate edge. The substrate may be either a printed circuit card or any other embodiment of contacts residing along an edge of a thin insulator membrane or flat plane. One or more series of chiclet modules may be held in specific alignment by means of their emplacement in groups, gangs, or arrays residing in an overall plastic or metal frame.
Alignment for mating a stacked series of chiclet assemblies with a series of known target objects, such as a 2-dimensional contact pad pattern, normally presents a challenge of tolerance stack-up of the individual assemblies; the positional error of the last assembly in a series is perturbed by the sum, or accumulated tolerances, of all of the elements between it and the known position of a datum or reference object such as an alignment structure. The present invention advantageously eliminates accumulated tolerance by providing positioning structures in the overall frame for each chiclet module.
The present invention entails an insulator chiclet module whose interior contacts are shielded to the maximum extent by one or more generally box-shaped or tube-shaped shields enveloping as completely as possible the plastic insulator and its internal contacts. These shields comprise a part of the chiclet module subassembly proper, and no other insulating, shielding, or grounding structures are required in the overall frame. Manufacture of the shields into their closed or nearly closed perimeter cross sections may proceed from seamless or extruded tubes or from flat sheet stock folded into box-like or tube-like structures. A single shield may envelop the entire insulator structure and the contacts contained within, or an insulator may be provided with two or more contact-isolating lobes and a set of shields of which envelop individual lobes as completely as possible. In this card edge embodiment, the insulator is bilaterally symmetrical about the midplane of the card it admits, and this insulator accepts two box-like shields, one on each side of the card midplane. The shields include their own contacts members, and either these or their designated pads on the card edges, or both, may be specially elongated or positioned so as to establish, in a pre-emptive manner, shielding or common electrical grounding across the contact interface, in advance of electrical interconnection of other sensitive signal lines.
In some cases, mutual electrical contact between the shields of neighboring contacts is preferred, and the invention provides for chiclet modules with spring tabs or fingers which contact neighboring chiclet modules. In cases where individual electrical potentials of neighboring shields are to be maintained separate, these neighboring contacts may be eliminated, or an insulating structure may be provided in the overall frame to interpose or defeat this shield-to-shield interconnection.
The chiclet modules of the invention are designed to provide electrical contact preferably to both sides of the engaged or inserted substrate, card, or membrane edge. Single-sided deployments are also within the scope of the invention.
The inventive device may engage pad patterns of uniform spacing or pitch, or of a repeated or a staggered series of non-uniform patterns, as is common with contact arrays of shielded differential signal pairs. Individual chiclet modules, including those which span several units of pad pattern pitch, may be provided which engage with locally unique patterns. An example of this case would be an assembled connector comprising a first series of shielded differential pair units with repeated patterns of contacts on a first pitch, a second series of non-shielded modules each of which present a gang of conventional contact pairs on a second pitch, and a third series of high current power modules comprising heavy-duty contacts on a third pitch.
Thus is described an assembly containing sub-assemblies of unspecified numbers of identical shielded, modular units, which may be interspersed with non-shielded units of lower cost and also special-purpose units such as those designed for high current interconnections. The invention provides an overall frame to precisely position these modules with no accumulated tolerance stack-up. Unit members of the pattern of positioning structures provided in the frame may individually accept modules of a unitary design, or as a group may accept larger modules spanning several of these positioning structures. If desired, one or more positions in this frame may be left empty, or a blank or dummy module may be provided. The pitches and patterns of the contacts residing within these modules are neither necessarily equal to nor necessarily related to the pitch and pattern of the positioning structures in the overall frame.
Simple card-edge connectors rely on one or both end walls of the connector to align it with the pad patterns residing on the card. It is also known that one or more intermediate notches may be provided along a card edge for polarity, identification, and for improved registration of the connector to the pad patterns on the card by means of including a plenum or stub in the connector which registers in the slot(s) under proper insertion. While it is possible to provide special-purpose chiclet modules each of which include local registration features, the cost of producing a series of complimentary mating features along the card edge is likely to prohibit this approach. Therefore, our invention preferably provides a primary alignment plenum or stub or a primary set of these, incorporated in the overall frame in a manner which defines a precise positional relationship between this alignment feature or feature set, and the series of positioning structures within the overall frame which align the chiclet module sets. These primary features in the overall frame provide initial and precise alignment of the chiclet modules to their associated patterns on the card edge, by means of the chiclet modules being engaged and registered by the series of positioning structures in the overall frame and by virtue of the fact that both the positioning structures and the primary alignment features are integral features of the overall frame. Therefore, the locational accuracy of the chiclet modules with respect to an alignment slot provided in the card edge (complimentary to the primary alignment feature of the frame) accrues no accumulated tolerances associated with the number, type, or distance from the frame""s primary alignment features to its positioning structures which locate the chiclet modules. By this arrangement, the locational accuracy of any particular chiclet module is limited only by the accuracy and reliability of the process used to provide the features of the overall frame.
While conventional housings designed to receive a series of modules often provide an individual aperture or receiving section for each individual module or insert, our overall frame provides one or a small series of large longitudinal openings each of which may accept our chiclet modules in groups. The positioning structures mentioned elsewhere reside nearby and extend within the general openings. Our chiclet modules are designed with complimentary features to accept precise alignment by these positioning features in the frame. According to the preferred embodiment, these features are common to all types of chiclet modules and all openings in the frame, which affords a maximum diversity of the combinations and compositions of groups of chiclet modules available for assembly into the overall frame. However, it is understood that sets of frames and chiclet modules may be designed with distinct families of positioning structures and features, whereby these frames, in offering a first set of positioning structures in any one aperture and a mechanically incompatible second and distinct series of positioning structures in any other aperture will prevent the mingling of one family of chiclet module designs with a second family of designs within the same aperture. This segregation may be advantageous as a polarity feature, or as a means of eliminating assembly operator error, or to provide a special and proprietary series of product distinct from a general commodity design. An additional advantage of such segregation is the separation and deliberate location of a distinct series of chiclet modules of an especially robust design capable of withstanding severe service, such as high voltages, high currents, or exceptional mating life demands, whose special positioning structures are mechanically incompatible with elements from the series of standard service designs. In this case, such segregation can advantageously prevent an undesirable or dangerous condition, including the untimely or catastrophic failure of an improperly positioned standard service unit or chiclet module group accidentally subjected to severe service.
Where a continuous wall or perimeter structure would occlude visual inspection of good manufacturing processes, such as successful solder reflow of surface mount contacts, or full and complete insertion of chiclet modules into the overall frame, the frame is preferably provided with apertures, or continuous longitudinal cut-away sections, or a pattern of cut-out profiles (e.g., perforated, invected, embattled, engrailed, etc.) affording such visual inspection by completely or intermittently revealing internal features, component positions, or the results of operations otherwise enclosed by the overall frame.
A primary feature, then, of the present invention is the provision of a modular electrical connector.
Another feature of the present invention is the provision of such a modular electrical connector in the form of a card edge connector with shielded modular inserts.
Still another feature of the present invention is the provision of such a modular connector including an elongated longitudinally extending outer frame defining a reception region adapted to receive a plurality of chiclet modules including contact members and lying in parallel laterally extending planes which, as an assembly, are positioned to connectively engage with mating contacts.
Yet another feature of the present invention is the provision of such a modular connector wherein each chiclet module includes an insulative housing having first and second spaced generally parallel elongated passages therein and a card receiving recess for reception therein between the first and second passages of a planar card having opposed surfaces with conductive contact members thereon, a first elongated contact firmly received in the first passage having a first contact surface positioned for engagement with a first of the mating contacts, a second elongated contact firmly received in the second passage having a first contact surface positioned for engagement with a second of the mating contacts, wherein the card receiving recesses of the plurality of chiclet modules as a group defines a longitudinally extending card receiving slot, the first elongated contact including a second contact surface projecting into the card receiving slot for engagement with a first conductive contact member on the planar card inserted into the card receiving slot and the second elongated contact including a second contact surface projecting into the card receiving slot in the direction of the first elongated contact for engagement with a second conductive contact member on the planar card inserted into the card receiving slot.
Still a further feature of the present invention is the provision of such a modular connector wherein a tubular ground shield is slidably received on the insulative housing in proximate engagement with its outer peripheral surface, the ground shield including a first integral ground contact for engagement with a ground contact of an external unit associated with the mating contacts engaged by the first contact surfaces of the first and second elongated contacts and a second integral ground contact for engagement with a ground contact surface on the planar card inserted into the card receiving slot.
Still another feature of the present invention is the provision of such a modular connector including first and second ground shields, each having a C-shaped cross section, slidably received, respectively, on the insulative housing in opposed relationship and in proximate engagement with its outer peripheral surface, the first ground shield generally overlying the first elongated passage, the second ground shield generally overlying the second elongated passage, the first ground shield having first and second opposed limbs proximately overlying the first and second major sides, respectively, a first side limb proximately overlying the first minor side, and a first flange limb extending transverse of the first opposed limb slidably received in the first elongated slot whereby the first ground shield substantially completely surrounds the first elongated contact received in the first passage, the second ground shield having third and fourth opposed limbs proximately overlying the third and fourth major sides, respectively, a second side limb proximately overlying the second minor side, and a second flange limb extending transverse of the third opposed limb slidably received in the first elongated slot whereby the second ground shield substantially completely surrounds the second elongated contact received in the second passage, the first and second ground shields both including a first integral ground contact for engagement with a ground contact of an external unit associated with the mating contacts engaged by the first contact surfaces of the first and second elongated contacts, each of the first and second ground shields including a second integral ground contact for engagement with an associated ground contact surface on the planar card inserted into the card receiving slot.
Other and further features, advantages, and benefits of the invention will become apparent in the following description taken in conjunction with the following drawings. It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory but are not to be restrictive of the invention. The accompanying drawings which are incorporated in and constitute a part of this invention, illustrate one of the embodiments of the invention, and together with the description, serve to explain the principles of the invention in general terms. Like numerals refer to like parts throughout the disclosure.